Press proofs are the only way to view
an accurate proof, but they can be costly. A press proof involves using
a press to generate a printed image before the actual pressrun. It is
used mainly to simulate printing processes using the actual plates,
inks, and paper. Note that the price of the job may include an additional
press set-up charge because of the time involved in producing the press
proof and then to set-up the press again when it is time to produce
the actual job. If changes are to be made after a press proof, there
would be additional costs involved if another press proof is required.
However, a press proof is the best type of proof, particularly for projects
using stochastic screening.

Note: When different RIPs are
used for proofing and imaging the plates, there is some risk that
some differences will occur.